private void btnDownload_Click(object sender, EventArgs e)
        {
            FolderBrowserDialog fbd = new FolderBrowserDialog();
            DialogResult result = fbd.ShowDialog();

            string bestandspad = fbd.SelectedPath + "/accounts.cvs";

            if (!string.IsNullOrWhiteSpace(fbd.SelectedPath))
            {
                File.Create(bestandspad).Close();
                StringBuilder sb = new StringBuilder();
                foreach (var user in users)
                {
                    sb.AppendLine(string.Join(";", user));
                }
                File.AppendAllText(bestandspad, sb.ToString());
                Console.WriteLine("");
            }

        }

        private void btnLogin_Click(object sender, EventArgs e)
        {
            username = txtUsername.Text;
            password = txtPassword.Text;

            userregel = new string[3];
            userregel[0] = username;
            userregel[1] = password;
            userregel[2] = hashPassword(password);
            users = new List<string[]>();
            users.Add(userregel);


        }

        private string hashPassword(string text)
        {
            string hashedPassword;

            char[] letters = password.ToCharArray();

            Array.Reverse(letters);

            foreach (var kar in letters)
            {
                password += kar;
            }

            string zoutenpeper = "$_MaxHash_" + password + "_999_" + "_#123";
            byte[] bytes = new UTF8Encoding().GetBytes(zoutenpeper);
            byte[] hashBytes;

            using (SHA512 shaM = new SHA512Managed())
            {
                hashBytes = shaM.ComputeHash(bytes);
            }

            hashedPassword = Convert.ToBase64String(hashBytes);

            return hashedPassword;
        }